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Cultivated land is the oldest and most extensive human-land system formed by human civilization through the transformation of the earth′s surface for thousands of years. The ability of cultivated land system to maintain stable production and healthy environment is reflected in the quality characteristics of cultivated land, under certain technical and economic conditions within a certain period of time, and the development and utilization value is expressed as the resource attribute of cultivated land. This paper clarifies the cultivated land system, the quality of cultivated land and cultivated land resources, on the basis of cognitive connotation and evolution process. The "nature - humanity" constituent elements and their coupling relationship of cultivated land resources are analyzed, characteristics and formation mechanism of "horizontal-vertical" structure, "production-ecology-living" function synergy and transformation relationship. The exchange process and response mechanism of "matter-energy-information", and the service value and evolution law of "economy-ecologysociety", the cognitive system of cultivated land resources is constructed, which is "two-dimensional factor-triple function-multiple value". A new way of systematically recognizing cultivated land resources is proposed, deconstructing the internal mechanism and external value of cultivated land resources, service farmland protection and quality improvement and natural resource assets "two unified" management, to support the construction of a new pattern of resource utilization and cultivated land protection under high-quality crossdomain development. [ABSTRACT FROM AUTHOR]

[Objective] In order to comprehensively maintain and improve the production, ecological and living functions of the farmland ecosystem, under the different types of cultivated land, the present paper analyzed the spatial and temporal evolution trajectory and characteristic differences of the quantity and quality of the water and dry land in the cultivated land based on the perspective of the ’trinity’ protection for quantitative and quality ecological development.[Method] Taking the Jiangjin District of the Three Gorges Reservoir as an example, the land use status and cultivated land quality grade evaluation result data, the standard deviation ellipse, landscape pattern index, nearest neighbor index method, etc. were used to study the quantity, the spatial and temporal evolution pattern of quality and ecology. [Result]（i） Quantity, the distribution of flooded and dry land in Jiangjin District had a trend of further expanding to the hinterland of Jiangjin District. The evolution path of dry land changes from northwest to southeast, and the evolution path of paddy field changed from southwest to southeast;（ii） Quality, the overall quality of the paddy field was higher than that of the dry land. The grade of the paddy and dry land was gradually decreasing from the central and western regions to the north and south.（iii） Ecological, the shape of the paddy and dry land was complex and fragmented, with reduced connectivity and significant aggregation.[Conclusion] The implementation of arable land zoning and types of protection measures, to achieve the development momentum of characteristic agriculture according to local conditions, provides reference for the protection of arable land resources in this area, the formulation of ’tri-in-one’ protection policies and the optimization of the layout of arable land. [ABSTRACT FROM AUTHOR]

For the factors affecting cultivated land quality vary with regions, classifying of land consolidation regions is the groundwork for farmland consolidation, which has great significance to improve the pertinence and effectiveness of the consolidation project. However, there exists some problems with the classification of large sample with multidimensional variable space, such as the classifying parameters being difficult to give and the result lacking visualization. In this paper, a new method called the graphical method of density diagram was put forward based on principal component analysis to improve the objectivity, visibility and interpretation of the classification. The processes were as follows: At the first, the method of principal component analysis was used to get the principal components from multiple factors, and then the values of first principal component (F1) and the second one (F2) of all the samples of Xinzheng City, Henan Province were calculated. Secondly, land consolidation regions were classified using cluster analysis method by making a scatter diagram of the samples in a two-dimensional plane of F1-F2 to create a scatter density figure. Finally, the types of land consolidation regions were subdivided by the method of parsing with the qualitative factors, such as landform type and soil texture. The study was performed in Xinzheng City, and the results showed that: 1) F1 and F2 contained 85.55% of the total information of the original factors including organic matter, total nitrogen, available phosphorus, available potassium of soil and irrigation rate, which could take the place of all of the original factors to classify land consolidation regions. 2) In the scatter density diagram of F1-F2, the obvious cluster feature was presented, by which different types of land consolidation regions could be classified effectively and objectively, and the types had clear connotations for F1 and F2 were well correlated with grain yield. 3) By cluster and analysis, the 315 administrative villages in Xinzheng City were divided into 6 types of land consolidation regions: the comprehensive factors limiting region, the available phosphorus-irrigation rate limiting region, and the available potassium and organic matter-irrigation rate limiting region with low grain yields; the potassium and organic matter-irrigation rate limiting region with medium grain yields; irrigation rate limiting region, and the unlimited region with a medium-high grain yield. The grain yield and factors features of the different types differed from each other. The conclusion can be given that the classification method put forward in this paper is suitable for farmland consolidation partition of large sample with multidimensional variable space, and the classification can be used in farmland consolidation in Xinzheng City. [ABSTRACT FROM AUTHOR]

Land consolidation projects could promote the cultivated land natural quality and improve the production conditions. It had certain value to study the influence of land consolidation project on cultivated land quality. In this paper, we took land consolidation project, which was constructed in the year of 2012, in Shanggao County of Jiangxi Province as the study area, and analyzed the influence of land consolidation project on cultivated land natural quality and production conditions. The land quality and production condition change was based on cultivated land grades before and after land consolidation on the basis of the last cultivated land quality grade annual updating results. Part of the factors which determined the cultivated land natural quality would be affected by the land consolidation project. In this study, the initial grading factors could be divided into two categories, the first were the stable factors, the attribute remained the same after the land consolidation project, and the second were the changing factors, the attribute changed after the land consolidation project. For these stable factors, in this paper, we took the original data directly. For these changing factors, we would collect the data after the land consolidation project through field investigation and indoor analysis. The weights and scoring rules of the natural quality grading factors stayed the same. Then we recalculated the natural quality index again. The canonical correlation analysis method was used to determine the land use correction factors from the influence factors of land consolidation project on the cultivated land production conditions. Then, we determined the weights of the factors on the base of Delphi method and analytic hierarchy process (AHP). The ratio of the scores before and after land consolidation was the land use correction coefficient and modified the original land use coefficient so that the revised land use index could be derived according to the original evaluation process. In the paper, we developed the cultivated land quality natural grade and the land use grade according to Agricultural Land Classification for Jiangxi Province. Then we compared and analyzed the changing situation of cultivated land quality grade before and after land consolidation. At last, in this paper, we used the multiple regression analysis methods to determine correction factors which had significant influence on the cultivated land quality. The land use correction factors were plots regularity, road network density, effective irrigation area index, distribution of the drought and flood. The results showed that the average natural quality grade were raised from 9.06 to 8.81 after the land consolidation, the general land utilization level increased 1.13 after the land consolidation. The average land use grade was raised from 6.03 to 4.68 after the land consolidation. The major influential factors of land consolidation project on cultivated land quality were organic matter content, soil pH, drainage, irrigation, plots regularity, road network density. The results demonstrated that the land consolidation projects could increase cultivated land quality and improve production conditions. It could accurately reflect the characteristics of the land consolidation project through the changing factors of cultivated land quality and the correction factors of land use. The method for agricultural land quality improvement and evaluation was feasible after land consolidation. The evaluation results could be used as the basis for the land management performance evaluation. [ABSTRACT FROM AUTHOR]

Cultivated land resource is the material base that mankind depend on for existence. Understanding how the cultivated land changes in quantity and quality has an important significance for country's food security and social stability. Based on the satellite images from Landsat TM/ETM in 2000 and OLI in 2013, this paper mapped the spatial distribution of cultivated land in the midwest Jilin province both in 2000 and 2013 and analyzed its temporal and spatial changes. Furthermore, soil data from 2351 field sampling points in study area were used to evaluate the quality of cultivated land and a comprehensive evaluation was made. Results revealed that cultivated land area in the midwest Jilin province increased from 5.61×104 km2 in 2000 to 5.64×104 km2 in 2013, among which dry farmland increased by 645 km2 and paddy field decreased by 350 km2.The transformation between dry land and paddy land was evident.Distribution of cultivated land changed differently from the east to the west:increasing in west part of study area and decreasing in east part, which resulted in the gravity center of cultivated land moved toward the west obviously. The increased cultivated lands were mainly converted from wetland and grassland, accounting for 66.04% and 21.12% of the total change area, respectively. The lost cultivated lands were mainly turned to artificial area, woodland and wetland with an area percent of 45.08%, 28.85% and 22.61%, respectively (mainly distributed around Changchun city). In terms of cultivated land quality, most cultivated lands were in uppermiddle grade in the midwest Jilin province in 2013, and the quality in the east part was better than that of the west.Although the total area of cultivated land increased, the quality of increased cultivated land mainly distributing in Baicheng and Songyuan city corresponded to lower grades including the third, fourth and fifth class with an area of 235,8 and 218 km2 respectively. Besides, the area of cultivated land in first class decreased by 305 km2, which mostly happened in the surrounding regions of Changchun city. The factors influencing the change of cultivated land were analyzed and we found that urbanization and policy were the most important driving forces to affect cultivated land quality and quantity. Accompanied by the rapid urbanization process, more and more highquality cultivated lands were occupied. Newly increased cultivated lands were mostly reclaimed from salinized land, alkalized land and wasteland, which led to an increase of cultivated land area and a decrease in quality. Overall, the cultivated land in the midwest Jilin province degraded severely during the past 15 years. This paper can provide an important reference for regional sustainable development of cultivated land resource. [ABSTRACT FROM AUTHOR]

The results of cultivated land quality gradation are made of the results of county, provincial, national levels. The results at the provincial level are integrated by the results at the county level. Provincial integration is an essential link in cultivated land quality grading work. The traditional provincial integration methods excessively depend on the provincial integration base map, which makes the integration efficiency low. Moreover, the quality of integration work completely depends on the quality of integration base map. Based on these defects, this paper comes up with a method that uses the grid instead of the integration base map. In provincial integration work, we need to build traceability relation between county units and provincial units. It requires all county units can find provincial units and all provincial units have their corresponding county units. Moreover, there is a principle we have to abide by: the ownership, the land type and the grade should be coincident between the county units and corresponding provincial units. That is "ownership-land type-grade" coincident principle. The purpose of this method is to make spatial distribution of provincial cultivated land quality is similar to that of the county when abiding by this principle. First we need to classify the county results according to "ownership-land type-grade". Then we determine the corresponding grid category according to the area dominant principle. Through the spatial nearest neighboring method, we find the grid unit closest to the unit at the county level to build "Grid-County grading unit" relations. But maybe there are some categories which can't be found in the provincial grids. Based this situation, the barycenter of the missing category was firstly calculated, then an uncultivated area grid closest to the barycenter was searched out, and lastly this grid was marked as the missing category. The grid coding method proposed in this paper stipulates that grid code is formed by county's administrative code, the grid rank, quality gradation and land class code. The length of the code is 21. At last, this paper uses the mean center and standard deviational ellipse to test the similarity of the spatial distribution of cultivated land before and after integration. This paper takes Daxing district, Bejing as a study area. By "ownership-land type-grade", there are 8 categories in Daxing. According to the distribution of cultivated land in Daxing district, 688 valid cultivated land grids were finally determined. Using the method in this article, we completed the integration at the provincial level for Daxing. After test, it showed that the difference of mean center between provincial grid results and county results is only 405.6 m, and the difference of distribution direction is only 0.34°, which means that this method can ensure the consistency of spatial distribution of cultivated land at different levels. Compared with the method which depends on the integration base map, the method based on grid doesn't make base map, reduces workload and improves work efficiency. This method orientates the provincial cultivated land into each grid and codes for these grids. Through grid code, we can quickly search cultivated land quality in the corresponding position, which is very convenient for both management and application. [ABSTRACT FROM AUTHOR]

Rapid industrialization and urbanization have brought a series of environmental problems related to soil pollution in the Pearl River Delta region. A systematic and synthetic evaluation of the cultivated land quality is of great significance to guide the rational utilization and protection of cultivated land, as well as to realize the comprehensive balance and management of cultivated land. However, the soil pollution factors have seldom been considered in cultivated land quality evaluation system, which was also short of a sensitivity analysis of the index weight. Based on GIS (geographic information system) multi-objective decision analysis, the paper conducted a study on the evaluation of cultivated land quality and the sensitivity analysis of index weight by taking Zengcheng District of Pearl River Delta as an example. With soil fertility factor and environmental assessment index taken into consideration, the comprehensive evaluation index system of cultivated land quality was constructed from 4 aspects: Soil physical and chemical properties, agricultural production conditions, location conditions and soil environment, so as to analyze the general characteristics of cultivated land quality and the spatial layout rule in Zengcheng District, and the weight sensitivity analysis of OAT (one-at-a-time) method was adopted to evaluate the influence degree of each index weight's uncertainty on the evaluation results. In order to reflect the trend and regularity of the changon cultivated land quality and its spatial pattern, the weight value of only one factor changed at a time while the other factors remained unchanged. When the value of RPC (range of percent change) and IPC (increment of percent change) were at ±30% and ±2% respectively, and every criterion factor was applied to all the evaluation indicators as the main change factor, a total of 420 groups of weight values were generated, among which every group of weights were calculated to produce a new evaluation result of the comprehensive quality of cultivated land. The main results of the study were as follows: 1) The cultivated land in Zengcheng District had a good overall quality, but high quality cultivated land was lacked. The grades of cultivated land quality were mainly concentrated at the 2nd and 3rd grade, which accounted for 30.88% and 31.69%, respectively. The proportion of middle and low yield field was relatively large. 2) From the perspective of the spatial distribution, the cultivated land with better quality was mainly distributed in the southern plains, the basins with better irrigation conditions like Zengjiang River basin, East River basin and Xifu River basin, as well as North River valley. The comprehensive quality of most cultivated land in Zhengguo, Xiaolou and Paitan was not high, and the overall quality of cultivated land in Xintang Town was poor. 3) The changes of weights had a certain influence on the quality distribution of cultivated land. Seen from the spatial distribution of change rate of cultivated land quality generated from different weight distribution, the spatial differences of the calculated results were rather big. When the weight increased or decreased by the same value, the same factor showed the same sensitivity to the quality evaluation results of cultivated land. 4) The maximum MACR (mean absolute change rate) value of 3.558 2% was much lower than the corresponding weight change rate of 30%, showing that the evaluation results were relatively stable, and the quality of cultivated land in Zengcheng District was overall stable. In conclusion, in the comprehensive evaluation of cultivated land quality, the soil environmental factors should be taken into consideration, and a quantitative analysis of micro-data of the soil pollution situation should be conducted to make the evaluation system more comprehensive and more scientific. The sensitivity analysis of the index weight can verify the reliability of the evaluation results, which can help the relevant departments make better decisions, and reduce the uncertainty in the spatial multi-criterion decision-making. [ABSTRACT FROM AUTHOR]

Cultivated land quality has important implications for agricultural benefit, food security, and sustainable utilization ability of cultivated land resources. To understand concept, composition, characteristics and influencing factors of cultivated land quality is important for strengthening basic research in cultivated land quality, promoting land remediation and high-standard basic farmland construction, and launching cultivated land quality management practice work. This paper discusses 3 current main concepts of cultivated land quality, analyzes connotations of quality and land quality, then expounds a new concept of cultivated land quality, and obtains the following main conclusions. 1) The current main 3 concepts of cultivated land quality based on natural attributes, natural-economic attributes and multiple attributes have evolutionary relationships, while they are coexistent and distinct. 2) Quality is the extent about a set of inherent characteristics of the product to meet the requirements; land quality is the ability and level of the specific land use type to meet some specific requirements. 3) Cultivated land is farming land, including not only land used to grow crops, but also roads, ditches, shelterbelts, ridges, electromechanical wells and other infrastructure land attached to these land and the drying field, seedling shed, agricultural stations and other ancillary facilities land. 4) Cultivated land quality is the level of the performances of cultivated land itself to meet the requirements of agricultural production and obtaining economic profits and human well-being. The cultivated land quality includes land fertility quality, engineering quality, space quality, ecology-environment quality and aesthetics-culture quality. Farmland productivity is cultivated production potential determined by soil fertility, geomorphology, climate, hydrology and other natural factors. Fertility quality is the core of cultivated land quality, the background quality or inherent quality of cultivated land. Cultivated engineering quality is embodied as the supporting extent and quality of water conservancy, transportation, electricity, ridge and other infrastructures, and seedling shed, drying field, drying ponds and other ancillary facilities for satisfying agricultural production. Cultivated engineering quality not only affects the degree of realization of production potential, but also has an important influence on convenience and economy of agricultural production. Engineering quality is an additional quality of cultivated land, but it is an important part of China's current high-standard farmland construction. Space quality mainly refers to the characteristics of spatial form and spatial distribution. Spatial form includes field's surface slope, shape and size. Spatial distribution includes degree of transportation convenience, labor radius and concentration ratio of cultivated land. Space quality affects the mechanization level, convenience level, scale level and efficiency of agricultural production, and then affects the economic profitability of cultivated land. Ecology-environment quality includes ecological quality and environmental quality. The former refers to soil and water conservation, air purification, climate regulation and other ecological service functions while cultivated land is regarded as an ecological subsystem. The latter mainly refers to soil environment capacity, and quality of soil environment, irrigation water environment and surrounding air of cultivated land. Aesthetics-culture quality is the aesthetic and cultural characteristics embodied by cultivated land. 5) The characteristics of cultivated land quality include productivity, internality, comprehensiveness, extensity and timeliness. Cultivated land quality is affected by natural factors, engineering factors, social factors and their combination conditions. No matter in the theory study or the management practice of cultivated land quality, it is necessary to treat cultivated land quality comprehensively and without bias, and to unify the objectivity of cultivated land quality and the subjectivity of cultivated land quality demand. We should select cultivated land quality indicators based on cultivated land evaluation purpose, build the evaluation index system scientifically, and monitor spatial scale and temporal frequency to evaluate the quality of cultivated land accurately. [ABSTRACT FROM AUTHOR]